Supernovas
Have you ever wondered what the hell a Supernova is, how it is
created and whether or not Oasis were making things up when they sung
about a Supernova made up entirely of Champagne? Well, it seems science
is not too far away from letting us know.
As discussed in a
recent report from ABC Science, it is believed that scientists
observing the early moments of a supernova have confirmed that some are
"caused by the destruction of white dwarfs". A white dwarf,
is a small star composed mostly of electron-degenerate matter which are
very dense with a mass comparable to that of the Sun and its volume is
comparable to that of the Earth.
White dwarfs are thought to
be the final evolutionary state of all stars whose mass is not high
enough to become a neutron star—over 97% of the stars in our galaxy.
What
does this all mean, well in short, the discovery confirms long believed
theory that these powerful explosions can outshine galaxies.
SN2011fe is located 21 million light years away in M-101 (Pinwheel galaxy) in the constellation Ursa Major.
Dr
Peter Nugent (United States Department of Energy's Lawrence Berkeley
National Laboratory) says that Type 1A supernovae are exploding stars
"characterised by an absence of hydrogen" long believed to be the most
abundant element in the Universe.
They are thought to be
caused by the explosion of white dwarfs that is part of a binary
system, drawing matter from the companion star.
As the white
dwarf accumulates matter, it eventually reaches about 1.4 times the
mass of the Sun, and then suddenly explodes, ripping itself apart.
Nugent noticed that the explosions converted large amounts of carbon
and oxygen into heavier elements such as nickel.
"A shock wave
rips through and ejects the material in a bright expanding photosphere.
Much of the brightness comes from the heat of the radioactive nickel as
it decays to cobalt" says Nugent.
"Light also comes from ejecta
being heated by the shock wave, and if this runs into the companion
star it can be reheated, adding to the luminosity" he noted.
A
second paper by scientist Dr Weidong Li discussed how Hubble and
Spitzer images looking for the white dwarf's companion star were able
to find red giants and bright stars with strong stellar winds called
helium stars which were likely binary partner stars not much bigger
than our Sun.
"It's important to understand as much as we can
about the objects that give rise to a type 1A supernova" says Dr Stuart
Ryder from the Australian Astronomical Observatory who suggests the
understanding of how type 1A supernovae form is important part in our
understanding of the cosmos.
"All type 1A supernovae explode
with similar characteristics, we use them as standard candles, to help
determine distances across the universe".
There information we
have yet to discover about these facinating galactical mind bogglers is
infinite - and that's what makes it all so exciting! |
